Material for Electrical/Electronic Use

ABSTRACT

The present invention provides an electrical/electronic material which has low contact resistance, excellent corrosion resistance, high hardness, high flexing strength and excellent processability. The electrical/electronic material is characterized by being composed of 20-40% by mass of Ag, 20-40% by mass of Pd, 10-30% by mass of Cu and 1.0-20% by mass of Pt and having a hardness of 340-420 HV at the time of precipitation hardening after metal forming and an adequate flexing strength.

TECHNICAL FIELD

The present invention relates to Ag—Pd—Cu alloy for electrical and electronic device.

BACKGROUND ART

Materials for electrical and electronic device are generally required to have properties of low contact resistance, excellent corrosion resistance and the like, thus expensive noble metals such as Pt alloy, Au alloy, Pd alloy, Ag alloy or the like are widely used.

However, according to the usage, a test probe pin or the like for a semiconductor integrated circuit is required to have properties of hardness and wear resistance other than low contact resistance and corrosion resistance.

In such a case, Pt alloy, Ir alloy or the like indicating a high hardness in a state of plastic forming, or Au alloy, Pd alloy or the like which are hardened by precipitation treatment are preferably used. (Refer to the Japanese Patent No. 4176133 as an example).

CITATION LIST Patent Literature

Japanese Patent No. 4176133

SUMMARY OF INVENTION Technical Problem

The test probe pin has various types (shapes) such as Cantilever, Cobra, and Spring or the like depending on the inspection target, and the required property is different for each.

In a case where hardness is the most important property, Pt alloy, Ir alloy or the like indicating a high hardness in a state of plastic forming, or Au alloy, Pd alloy or the like indicating a high hardness in a state of precipitation hardening treatment is processed, are recommended.

However, generally high hardness materials have a property of frailty or weakness to folding.

Thus, types of probe pin with its tip folded by folding process may become fractured at the folding point of the probe pin due to stress applied to the folding point generated during the folding process or when it is used as a probe pin.

Accordingly, materials having properties of folding strength in addition to low contact resistance, corrosion resistance, and hardness is required for types of probe pin with its tip folded by folding process.

Solution to Problem

Hence, the present invention provides an electrical and electronic material which improves the mechanical property as alloy, that is, a hardness of the alloy is HV 340-420 after plastic forming and precipitation hardening treatment is processed to the alloy material, and improves folding strength and corrosion resistance by adding 1.0-20 mass percent Pt of a specific element to 20-40 mass percent Ag, 20-40 mass percent Pd, 10-30 mass percent Cu.

Herein, the reason the additive amount is 1.0-20 mass percent Pt is to improve the folding strength. If the amount is less than 1.0 mass percent, the improvement effect of folding strength is not obtained and if the amount is more than 20 mass percent, a specified hardness is not obtained.

To an alloy in which Pt is added to Ag—Pd—Cu, 0.1-10 mass percent Au and 0.1-3.0 mass percent of at least one of Re, Rh, Co, Ni, Si, Sn, Zn, B, and In as additive elements to improve the property according to the usage are further added.

The reason for adding 0.1-10 mass percent Au is to improve the hardness and to obtain the oxidation resistance. It is not effective if the amount is less than 0.1 mass percent, and processability is lowered if the amount is more than 10 mass percent.

Further, the reason for adding 0.1-3.0 mass percent of at least one of Re, Rh, Co, Ni, Si, Sn, Zn, B, and In is to improve the hardness. It is not effective if the amount is less than 0.1 mass percent, and processability is lowered if the amount is more than 3.0 mass percent. Re, Rh, and Ni also serves as effective materials for refining crystal grain.

Advantageous Effects of Invention

The electrical and electronic material of the present invention has properties of low contact resistance, excellent corrosion resistance, high hardness, high folding strength, and excellent processability.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is an explanatory view illustrating a folding test.

DESCRIPTION OF EMBODIMENTS

The embodiment of the present invention will be described with Table 1.

In the present embodiment, an alloy ingot (dia. 10 mm×L 100 mm) in which Pt was added to Ag—Pd—Cu alloy in vacuum melting was prepared.

After removing a melted defecting part such as shrinkage cavity or the like, the alloy ingot was subjected to drawing and solution treatment (800° C.×1 hr in a mixed atmosphere of H₂ and N₂) which were repeated to reduce the diameter to dia. 2.0 mm and was subjected to drawing so as to have a final sectional reduction rate of about 75% to obtain a test piece (dia.1.0 mm×L 200 mm). The condition of precipitation hardening treatment was 300-500° C.×1 hr in a mixed atmosphere of H₂ and N₂. Further, the hardness evaluation of the test piece was performed with a Vickers hardness testing machine in the scale of HV 0.2.

The folding strength was examined as shown in FIG. 1 in that the test piece was fixed with jigs with R 0.5 and folded repeatedly until the test piece became fractured, and the number of folding until fracture was counted. Folding by 90 degrees was counted as one, and zero means it did not fold by 90 degrees.

Table 1 illustrates the composition of each example, the folding number until fracture, the hardness of rolled material and precipitation hardened material.

TABLE 1 Table 1 Numbel of Hardness(HV0.2) folding Precipitation Composition(mass %) until Rolled hardened Ag Pd Cu Pt Au Re Rh Co Ni Si Sn Zn B In fracture material material Example1 33.00 40.00 17.00 10.00 5 285 385 Example2 20.00 37.00 12.80 20.00 7.00 0.20 3.00 4 325 420 Example3 29.00 39.70 10.00 11.00 10.00 0.10 0.20 4 310 390 Example4 33.00 20.00 30.00 9.00 0.10 0.90 3 315 340 Example5 20.00 32.00 15.70 20.00 0.10 0.10 0.10 4 300 410 Example6 29.00 35.00 28.90 1.00 0.10 3 295 380 Conventional 33.00 40.00 27.00 0 280 440 example1 Conventional 20.00 38.00 26.00 6.00 0 300 460 example2 Conventional 29.00 40.00 20.00 10.00 0 280 455 example3 Conventional 33.00 30.00 30.00 1 290 380 example4 Conventional 20.00 39.90 20.00 0.10 0 290 420 example5 Conventional 29.00 35.00 30.00 1 280 390 example6

According to the result shown in Table 1, the precipitation hardened material in Comparative example in which no Pt was added to Ag—Pd—Cu had low folding strength and fractured after folding of no more than 2 times, while the precipitation hardened material in example 1 in which Pt was added improved the folding strength and folding of 2 times or more was possible.

Similarly, the precipitation hardened material of alloy in which Pt and at least one of Au, Re, Rh, Co, Ni, Si, Sn, Zn, B, and In are added to Ag—Pd—Cu according to the Examples 2 to 6 achieved folding of 2 times or more. 

1. An electrical and electronic material comprising an alloy containing 20-40 mass percent Ag, 20-40 mass percent Pd, 10-30 mass percent Cu, and 1.0-20 mass percent Pt, having a hardness of HV 340-420 after plastic forming and precipitation hardening treatment is processed to said material, and having a high folding strength.
 2. An electrical and electronic material comprising the alloy of claim 1 to which 0.1-10 mass percent Au, and 0.1-3.0 mass percent of at least one of Re, Rh, Co, Ni, Si, Sn, Zn, B and In are added as additive elements to improve the properties according to the usage. 